Pressure relief element, pressure relief device and battery

Abstract

The present invention relates to a pressure relief element ( 11 ) to be used as an overpressure safety means in devices where a gaseous medium must be rapidly released in case of overpressure, wherein the pressure relief element ( 11 ) has at least one notch ( 9 ) which is designed as a predetermined breaking point where the pressure relief element ( 11 ) breaks at a certain level of overpressure, thereby irreversibly opening an exhaust path for the gaseous medium. The present invention also relates to a pressure relief device of an electrochemical battery, comprising such a pressure relief element and a battery comprising such a pressure relief device.

The invention claimed is: 
     
       1. A battery, comprising:
 a plurality of battery cells disposed within a battery housing, wherein the battery housing includes a pressure relief device comprising:
 an exhaust extension which extends outwardly from the battery housing; and 
 a fixation element for fixing the exhaust extension to a housing wall of the battery housing such that the exhaust extension traverses an exterior opening in the housing wall of the battery housing and is attached to the fixation element within the interior of the battery housing, wherein the exhaust extension comprises an injection molded plastic pressure relief element having:
 a first side having a profiled surface that is in fluid communication with an exterior of the battery housing; and 
 a second side, opposite the first side, having a substantially flat surface that is in fluid communication with an interior of the battery housing, wherein the second side comprises a notch that is a predetermined breaking point where the pressure relief element is configured to break at a certain level of overpressure of a gaseous medium in the battery housing, thereby irreversibly opening an exhaust path for the gaseous medium to rapidly exit the battery housing. 
 
 
 
     
     
       2. The battery of  claim 1 , wherein the injection molded plastic pressure relief element is formed as a plate-like and/or disc-like part. 
     
     
       3. The battery of  claim 1 , wherein the first side is an injection side of the of the injection molded plastic pressure relief element. 
     
     
       4. The battery of  claim 1 , wherein a thickness of the injection molded plastic pressure relief element is larger in a central area of the injection molded plastic pressure relief element than in at least one area surrounding the central area. 
     
     
       5. The battery of  claim 4 , wherein the thickness of the injection molded plastic pressure relief element decreases in a steadily declining manner from the central area towards the at least one area surrounding the central area. 
     
     
       6. The battery of  claim 1 , wherein the injection molded plastic pressure relief element comprises a circumferential area of increased material thickness on its outer circumference. 
     
     
       7. The battery of  claim 6 , wherein the notch is located close to the circumferential area with increased material thickness. 
     
     
       8. The battery of  claim 1 , wherein the notch is shaped as a circumferential notch, which surrounds a central area of the injection molded plastic pressure relief element. 
     
     
       9. The battery of  claim 1 , wherein the plastic material of the pressure relief element is a rigid plastic material. 
     
     
       10. The battery of  claim 1 , wherein the pressure relief element is a membrane. 
     
     
       11. The battery of  claim 1 , wherein the exhaust extension comprises a tube that is mounted by a tube connector and that allows constant pressure equalization between the interior and the exterior of the battery housing while the injection molded plastic pressure relief element remains intact. 
     
     
       12. The battery of  claim 1 , wherein the exhaust extension comprises a protection cap or maze that at least partly shields the pressure relief element against an environment exterior to the battery housing. 
     
     
       13. The battery of  claim 1 , wherein the plurality of battery cells are lithium ion battery cells. 
     
     
       14. The battery of  claim 1 , wherein the plurality of battery cells are cylindrical battery cells. 
     
     
       15. A battery, comprising:
 a plurality of battery cells disposed within a battery housing, wherein the battery housing includes a pressure relief device, comprising:
 an injection molded plastic pressure relief element comprising:
 a first side having a profiled surface that is in fluid communication with an exterior of the battery housing; and 
 a second side, opposite the first side, having a substantially flat surface that is in fluid communication with an interior of the battery housing, wherein the second side comprises a notch that is a predetermined breaking point where the pressure relief element is configured to break at a certain level of overpressure of a gaseous medium in the battery housing, thereby irreversibly opening an exhaust path for the gaseous medium to rapidly exit the battery housing; and 
 
 a tube that is mounted by a tube connector and that allows constant pressure equalization between the interior and the exterior of the battery housing while the injection molded plastic pressure relief element remains intact.